Hydraulic pump and system



Aprl 18, 1950 w. R. ''UCKER HYDRAULIC PUMP AND SYSTEM Filed March 25, 1944 INVENTOR WAREEN R.TUCKEE A TORNE`x'5 Patented Apr. s, 1950 HYDBAULIC PUMP AND SYSTEM Wrren B. Tucker, Dayton, Ohio, miglior to H-P-M Development Corporation, Wilnlngton, Del., a oorporatio ot Delme Application March 35, 1944, Serial No. 528359 (CI. IOS-S'U This invention relates to press systems, and in particular to systems tor small presses such as laboratory presses.

The general arrangement of this invention comprises a double acting ram to which is supplied pressure fluid by a manually operated pump. The direction o! reciprocation o! 'the differential ram is determined by the operation of a, threeway valve, the forward stroke being obtained by admitting pressure fluid to both sides of the difi'erentia ram, and the retraction stroke being obtained by exhausting the main area of the ram and supplying fluid to the retraction area.

The object oi' this invention is to obtain rapid closing, rapid opening and high pressure pressing by the ram.

It is an additional object of this invention to provide a muiti-stage pump operable by a com mon actuating means and selectively operabie as to each stage according to the position of the actuating means. It is therefore possible to get high speed action of a hydraulically actuated member such as a ram with relatively low pressure and then eiiect a reduced speed of the ram at increased pressure. v

This invention will be more clearly understood upon reference to the following decription and accompanying drawings in which:

Figure 1 is a diagrammatic lay-out of the press system. e

Figure 2 is a longitudina section through the manually operated pump,

Figure 3 is a transverse section through the pump and is indicated by the line 3-3 on Figure 2,

Figura 4 is a longitudinal section through the three-way valve.

Referring now to Figure 1, the diiierential pressure ram is indicated at u and is reciprocable within a cylinder I I. A manually operated pump at |2 supplies pressure fluid to a conduit l3 leading to the retraction area of the differential ram n, and to a conduit ll leading to a three-way valve !5 actuated by an adjustable handle mechanism lia.

The three-way valve is connected, by means of a conduit IS, with the main area of the ram ID, and by means of the ports l'l with a reservoir indicated at s. The three-way valve !5 is manually operable to close oi! the ports IT while simultaneously interconnecting the conduits Il and II. or to close oil' the conduit N while simultaneously interconnectirg the conduits IS and ports Il.

Rei'erring now to Figures 2 and 3, the construction of the pump !2 will be more clearly apparent. The pump comprises a, casing 20 having therein a bore 2| which is shouldered as at 22. An inlet port at 23 serves to admit fluid to the interior of the pump casing, and an outlet port 24 serves as an exit !or the pressure fluid from the pump casing. Check vaves 23' and 24' are suitably located in the ports 28 and 24 so as to prevent reverse flow therethrough.

Mounted within the bore 2| is a plung'er 25 which is urged by means of a spring 25a to the left to engage the shoulder 22. Reciprocation oi the plunger 25 within the bore 2l is' eflective to draw fluid in through the port 23 and to force it outwardly through the port 24. Reciprocation oi' the plunger 25 is brought about by oscillation of the shat 26 and arm 21. The arm 21 is pinned to a yoke which abuts the piston 25, and has threaded therein the smaller diameter plunger 28.

It will be apparent that oscillation of the arm 21 to. the right of center will be effective to move the plunger 25, and that oscillation of the arm to the left of center will be effective to reciprocate the plunger 28 independently of the plunger 25.

The'pump is preferably mounted within the reservoir and the shaft 28 extends exterioriy thereof and has fastened thereto a handle 29, as shown in Figure 1.

Rererring now to Figure 4, the construction of the three-way valve !5 is more clearly shown. This valve comprises a valve casing having three ports therein with which communicate the conduits ll, IS and II as sh own in Figura 4. A movable valve element 30 is reciprocated by means of the handle !sa and a threaded stern 32 to a right hand position to close off the -port with which the conduit H communicates, or to a left hand position to close oil the port with which the ports l'l communicate. In this way, the onduit IB is connected selectively to the conduit N or to the ports l1. i

As in the case of the pump, the valve |5 is preferably mounted within the reservoir with the handle lsa external thereof.

operation Assuming that the press is open, that is the ram lo is in its downward position, a fast closing stroke is instituted by moving the valve member 30 of the valve IS to the left to close off the ports I'I. The operator then oscillates the handle 29 so as to reciprocate the plunger 25 within. the bore 2l, that is, the hande 29 is reciprocated to the right of its center position, as viewed in Figure 2. A rapid closing results from this and continues until the work ram n engages the work.

When the work ram o engages the work, pressure builds up within the cylinder II and in the pump casing |2 thereby 'making reciprocation of the plunger 25 more dimcult. When the load on the plunger 25 becomes great enough to cause oscillaton of the handle 29 to become diflicult, the operator commences to oscillate the ha'ndle 29 to the left of center rather than to the right.

This is efl'ective to cause reciprocation of the small plunger 28 independently of the large plunger 25. 'I'he flow or fluid through the pump zo is reduced and the pressurethereof is substantially' increased. The working portion oi the' forward stroke is thus carried out at reduced speed 'and at increased pressure.

The work stroke of the ram o having been accomplished, the retraction stroke is accomdelivered to the retraction area on top of the head Ina to retract the ram Io within the cylinder ll.

The two-stage pump is of simple construction and provides 'means for obtaining 'a largevolume of flow at low pressure, or smaller Volume of flow at higher pressures. The valve IS is likewise of simple construction and provides a ready means of selecting between the forward and'retraction stroke.

It will thus be seen that there has been provided a two-stage pump operable selectively by the same actuating means in order to produce dififerent pressures and differentspeeds of delivery of the fluid. This is used in combination with the multi-way valve for controlling the direction of flow from the pump and both the pump and the valve are associated with a com mon reservoir for fluid that is used to actuate the ram and the ram itself is of the differential y will be understood that a great variety of different constructions may be employed while still embodying the invention of this application as set forth in the specification and particularly as set forth in the hereinafter rected claims. While I have referred to a laboratory press it will be understood that this is only illustrative and this invention is applicable to a wide variety of structures of different sizes and uses.

Havin thus fully described my invention what I claim as new and desire to secure by Letters Patent is:

1. A pump that includes in combination, a pump cylinder, piston means for producin flow through said cylinder, resilient means holding said piston means normally in an inoperative position, a second and smaller piston means reciprocable in said first piston means -for also producing flow through said cylinder, and an actuating means directly connected with said second piston and having two selective positions of movement in one of which 'concomitant operation of both of said piston means is obtained and in the other of which operation of said second piston means only is obtained.

2. In a. pump, a pump cylinder having a shouldered bore, a shoulder piston in said bore, a spring in said cylinder urging said piston in the direction to bring the shoulder thereof in engagement with the shoulder in said bore, a plunger extending through said piston, means connected with said plunger on the side of said piston opposite said spring for reciprocating said plunger, said means being adapted to abut said piston in a predetermlned position, and a pivot-- ed lever connected with said means whereby oscllation of said lever on one side of a predetermined line will produce reciprocation of said plunger and oscillation of said lever on the other side of a predetermined line will produce recip rocation of said piston and plunger in unison.

3. In a pump, a pump oylinder having a shouldered bore therein, a. shouldered piston reciprocably mounted in said bore, a spring in said cyl- Oscillation of" the pump handle !S will now cause fluid to be 4 y inder urging said piston therein in a direction to bring the shoulder thei-eo! in engagement with the shoulder in said bore, a plunger reciprocable through said piston. a block Secured 'to said plunger on the side of said piston opposite said spring, said block bein adapted !or abutting said piston, inlet and outlet means for said cylinder, and a lever pivoted to said cyl- .inder and connected with said block whereby oscillation of said lever on one side of a predetermined line will reciprocate said plunger alone and oscillation of said lever on the other side of said line will produce reciprocation of said plunger and piston in unison.

' 4. In a pump, a pump oylinder having a shouldered bore therein, a shouldered piston reciproca-bly mounted in said bore, a spring in said cylinder urging said piston therein in a direction to bring the shoulder thereof in engagement with the shoulder in said bore, a plunger reciprocable through said piston, a block Secured to said plunger on the side of said piston opposite said spring, said block being adapted for abutting said piston, inlet and outlet means for said cylinder, a lever pivoted to said cylinder and connected with said block whereby oscillation of saidlever on one side of a predetermined line will reciprocate said plunger alone and oscillation of said lever on the other side of said line will produce reciprocation of said plunger and piston in unison and resilient sealing means positioned between said plunger and piston and between said piston and cylinder.

'5. In a pump, a pump cylinder having a shouldered bore therein, a shouldered piston reciprocably mounted in said bore, a spring in said cylinder urging said piston therein in a direction to bring the shoulder thereof in engagement with the shoulder in saidbore, a plunger reciprocable through said piston, a block secured to said plunger on the side of said piston opposite said spring, said block being `adapted for abutting said piston, inlet and outlet means for said cylinder, a lever pivoted to said cylinder and connected with said block whereby oscillation oi' said lever on one side of apredetermined line will reciprocate said plunger' alone and oscillatlon of said lever on the other side of said line v. will produce reclprocation of said plungeand piston in unison, annular grooves around said plunger and around the outer periphery of said piston and annular resilient sealing members in 'said grooves tor sealing between said plunger a; and piston and between said piston and cylinder.

WARREN R. TUCKER.

REFERENCES CITED The following references are of record in the flle of this patent: 

